Black Diamond Mines Regional Preserve

A century and a half ago, coal fed the furnace of the Industrial Revolution. So crucial was coal to the cause that it was dubbed “black diamond.” When in 1973 the East Bay Regional Park District (EBRPD) acquired the property in Antioch now known as Black Diamond Mines, park officials knew what they were getting: the heart of Contra Costa’s historic coal and sand mine workings. In the words of EBRPD General Manager Bob Doyle, “We discovered a park with a lot of holes in it.”

Misty morning at the intersection of Stewartville and Ridge trails. In the background rises Mt. Diablo's North Peak.

Miniature lupine crowds the shoulder of Upper Oil Canyon Trail.

The price of mining nearly 4 million tons of coal from hundreds of miles of underground workings was steep. The gravestones of Rose Hill Cemetery divulge none of the details, but cave-ins, gas explosions and machinery-related accidents were common. Disease was a chief contributor to the cemetery’s population. Children were especially vulnerable to diphtheria, typhoid, scarlet fever and smallpox.

By the time human hands began digging into it, as Mine Manager John McKana put it, “The whole area was like a big layer cake tilted at 30 degrees and shuffled up 29 feet at the Hazel-Atlas Fault." The result is a realm of wonder, where you can run your fingers across exposed strata in snaking patterns frozen in time; peek through openings in the tunnel wall into stopes, a chain of mini-cathedrals scooped from the sandstone.